不明白为什么创建父类数组传入的对象可以是强制转换的子类

Animals[] a = new Animals[5];

for (int i = 0; i < a.length; i++) {

Random random = new Random();

int b = random.nextInt(3) + 0;

if (b == 0) {

Animals c = new Catc();

Catc catc = (Catc) c;

a[i] = catc;

} else if (b == 1) {

Animals e = new Dogd();

Dogd dogd = (Dogd) e;

a[i] = dogd;

} else {

Animals f = new Sheep();

Sheep sheep = (Sheep) f;

a[i] = sheep;

}

a[i].cry();

}